1. Introduction
The nitrogenous bases known as «purines» and «pyrimidines» are two of the essential building blocks of
deoxyribonucleic (DNA) and ribonucleic acid (RNA)
1. The derivatives of purine are adenine, guanine, xanthine,
hypoxanthine and the derivatives of pyrimidine are thymine, cytosine and uracil. The purine and pyrimidine bases in
cells are linked to carbohydrate and in this form are termed, nucleosides which are found in the cell primarily in